1. Field of the Invention
The present invention relates to a soft gelatin capsule which is easy to chew and is not sticky, and which is suitable for encapsulating, for example, pharmaceuticals, food, and health food. Further, the present invention relates to a soft gelatin capsule which is easy to twist open with the fingers, and is suitable for encapsulating, for example, pharmaceuticals, cosmetics, and food.
2. Description of the Background Art
Children and the elderly often experience difficulty in swallowing and ingesting medicines in solid forms, such as tablets, pills, and capsules. Pharmaceuticals in forms which permit easy ingestion and whose active components are rapidly released in the oral cavity are desirable in the event of a medical emergency such as an attack of angina pectoris.
Recently, with diversification of personal preferences in food, texture of food within the mouth is being addressed. For example, nata de coco, a food having a chewy texture, was very popular a short time ago.
Among solid medicines having elasticity, mention may be given of a soft gelatin capsule. In a conventional soft gelatin capsule, ingredients are encapsulated in a gelatin shell which is produced by extending a mixture of gelatin, plasticizer, and water into a thin sheet. Generally, the shell of a soft gelatin capsule is produced by adding, to gelatin, a plasticizer in an amount of 30-40 wt. % with respect to the gelatin; and drying the shell until the water content becomes 5-10 wt. %, so as to prevent the capsule from being deformed or becoming undesirably sticky.
The soft gelatin capsule prepared as described above is hard and tough, because it is designed to dissolve after reaching the intestines so as to release its contents therein. Therefore, the capsule is not easily broken in the mouth by teeth and is not suitable for chewing.
Also, because the conventional soft gelatin capsule is hard and tough as described above, twisting the capsule open by the fingers is difficult in practice, and opening the capsule requires a tool such as scissors. Therefore, the conventional capsule is unsuitable for external-use compositions and cosmetics which are removed from the capsule before use, as well as medicines which are required to be quick-acting.
One measure for further softening a soft gelatin capsule is to increase plasticizer content. This makes a soft gelatin capsule more likely to stick to another soft gelatin capsule or to a container, thereby causing deterioration in storage stability. Thus, increasing plasticizer content is inappropriate in a high-temperature, high-humidity region such as Japan. Also, a soft gelatin capsule of high plasticizer content tends to stick to, for example, the teeth during chewing.
In view of the above-described circumstances, the present inventors conducted earnest studies and found that increasing by several fold the amount of a plasticizer conventionally used for forming a gelatin shell and incorporating insoluble cellulose therein yields a soft gelatin capsule which has a soft, pleasant chewing texture and low stickiness and can be easily and reliably twisted open with the fingers. The present invention has been achieved on the basis of this finding.